CN108254947B

CN108254947B - Display device

Info

Publication number: CN108254947B
Application number: CN201711292217.4A
Authority: CN
Inventors: 方崇仰; 王文俊; 徐熊群
Original assignee: Coretronic Corp
Current assignee: Coretronic Corp
Priority date: 2016-12-29
Filing date: 2017-12-08
Publication date: 2020-12-22
Anticipated expiration: 2037-12-08
Also published as: CN108254947A; US20180188603A1; TWI605287B; US10429679B2; EP3343282A1; TW201823819A; EP3343282B1; JP2018109756A; JP6968684B2

Abstract

The invention relates to a display device which comprises a backlight module, a switching type single-shaft diffusion sheet and a display panel. The backlight module generates light, and the light has a first light type. The first light pattern has light intensity above a predetermined value in a first viewing angle range in a first direction. The produced light-emitting of backlight module produces the image through switching formula unipolar diffusion piece and display panel according to the preface, and when switching formula unipolar diffusion piece was switched into transparent state, the light-emitting keeps first light type behind through switching formula unipolar diffusion piece, and when switching formula unipolar diffusion piece was switched into the scattering state, the light-emitting was diffused and produced the second light type behind through switching formula unipolar diffusion piece. The second light pattern has a light intensity above a predetermined value within a second viewing angle range in the first direction, and the second viewing angle range is greater than the first viewing angle range.

Description

Display device

Technical Field

The present invention relates to a display device, and more particularly, to a display device capable of switching a display viewing angle.

Background

When a conventional handheld display device, such as a display provided in a mobile phone or a tablet computer, is used outdoors, the brightness of the display is relatively insufficient due to strong external light, so that the contrast of the image of the display is low, and the user often cannot see the image clearly. Existing solutions are backlight modules that use more light sources or drive the light sources of the backlight module with higher currents. If more light sources are used, the manufacturing cost increases and more power needs to be consumed, and if higher currents are used to drive the light sources, the lifetime of the light sources is reduced and more power is consumed.

The background section is provided to aid in understanding the present disclosure, and thus, the disclosure in the background section may include other art that does not constitute a part of the common general knowledge of the skilled person. Furthermore, the statements made in the "background" section do not represent that which is or is to be read as being known or that is known by those skilled in the art before the present application or the problems that may be solved by one or more embodiments of the present invention.

Disclosure of Invention

In view of the above, the present invention provides a display device, in a place with strong external light, a backlight module of the display device provides a light type with a narrow viewing angle and high luminance, so that a user can clearly view an image displayed by the display device, and in a place with weak external light or indoor, a backlight module of the display device provides a light type with a wide viewing angle and low luminance, so that a user can clearly view an image displayed by the display device in a wide viewing angle range.

Other objects and advantages of the present invention will be further understood from the technical features disclosed in the present invention.

To achieve one or a part of or all of the above or other objects, the present invention provides a display device including a backlight module, a switchable uniaxial diffuser, and a display panel. The backlight module is suitable for generating light, and the light is provided with a first light type which has light intensity more than a preset value in a first visual angle range in a first direction. The switching type uniaxial diffusion sheet is arranged on the backlight module and is switched between a transparent state and a scattering state, and the diffusion angle of the scattering state in the first direction is larger than that in other directions. The display panel is arranged on the switching type single-shaft diffusion sheet. The produced light-emitting of backlight module produces the image through switching formula unipolar diffusion piece and display panel according to the preface, when switching formula unipolar diffusion piece is switched into transparent state, the light-emitting keeps first light type after through switching formula unipolar diffusion piece, when switching formula unipolar diffusion piece is switched into the scattering state, the light-emitting is diffused and produces the second light type after through switching formula unipolar diffusion piece, the second light type is light intensity that light has more than the default value in the second visual angle scope on the first direction, and second visual angle scope is greater than first visual angle scope.

The display device of the invention adopts the light-gathering backlight module and the switching type single-axis diffusion sheet, and utilizes the characteristic that the switching type single-axis diffusion sheet can be switched between a transparent state and a diffusion state, thereby adjusting the scattering angle of the light emitted by the backlight module, when the external light is strong, the switching type single-axis diffusion sheet is switched to a transparent state, so that the light is concentrated in a certain visual angle range to obtain higher brightness, so that a user can watch a clear image, in the environment with weak external light, the display device does not need high brightness, the switching type uniaxial diffusion sheet is switched to a scattering state, so that the light emitted by the light-gathering type backlight module is diffused, the image brightness in a specific visual angle range can be reduced, the discomfort of the user caused by over-brightness can be avoided, the image brightness outside the specific visual angle range can be improved, the visual angle range is expanded, and the user can see clear images in a larger visual angle range. Therefore, the display device of the invention does not need to additionally increase the light source and the current for driving the light source, and the brightness of the display device can be adjusted corresponding to the light intensity of the external environment by utilizing the switching type single-shaft diffusion sheet.

In addition, the display device of the invention also comprises a semi-transparent visual angle filter which attenuates the brightness below a preset value outside a preset visual angle range and is matched with the characteristic that the switching type single-shaft diffusion sheet is switched between a transparent state and a diffusion state, when the switching type single-shaft diffusion sheet becomes the transparent state, the brightness is attenuated to an invisible state outside the preset visual angle range, when the switching type single-shaft diffusion sheet becomes the diffusion state, the overall brightness is relatively average, and the brightness is still visible outside the preset visual angle range, so that the display device of the invention has the peep-proof effect and can be switched between the peep-proof mode and the non-peep-proof mode.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic structural diagram of a display device according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a light path of the display device shown in FIG. 1 in a transparent state on a switching uniaxial diffuser viewed from an X-Z plane.

FIG. 3A is a schematic diagram of a light path of the display device shown in FIG. 1 when the switchable uniaxial diffuser is in a scattering state as viewed from a Y-Z plane.

FIG. 3B is a schematic diagram of the light path of the switching uniaxial diffuser of the display device shown in FIG. 1 in a scattering state when viewed from the X-Z plane.

Fig. 4 is a schematic structural diagram of a backlight module of the display device shown in fig. 1.

Fig. 5 is a schematic structural view of a switching uniaxial diffusion sheet of the display device shown in fig. 1.

FIG. 6A is a schematic diagram of a light path of the switching uniaxial diffuser in a scattering state of the display device shown in FIG. 1 viewed from an X-Z plane.

FIG. 6B is a schematic diagram of the light path of the switched uniaxial diffuser in a scattering state of the display device shown in FIG. 1 viewed from the Y-Z plane.

Fig. 7A and 7B are schematic views showing a transparent structure of the switching uniaxial diffuser of the display device shown in fig. 1.

FIG. 8 is a schematic diagram of the structure and optical path of another embodiment of the display device of the present invention, wherein the switching uniaxial diffuser is in a transparent state.

FIG. 9 is a schematic diagram of the structure and light path of the display device of FIG. 8, wherein the switchable uniaxial diffuser is in a scattering state.

FIG. 10 is a graph showing the relationship between the transmittance and the angle of transmitted light of the transflective viewing angle filter of the display device shown in FIG. 8.

Fig. 11 is a schematic structural diagram of the transflective viewing angle filter of the display device shown in fig. 8 according to an embodiment of the invention.

Fig. 12 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 13 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 14 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 15 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 16 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 17 is a schematic structural diagram of another embodiment of the transflective viewing angle filter of the display device shown in fig. 8.

Fig. 18 is a schematic structural diagram of a transflective viewing angle filter of the display device shown in fig. 8 according to another embodiment of the present invention.

Fig. 19 is a schematic structural view of a transflective viewing angle filter having a plurality of transflective barrier ribs.

Detailed Description

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of a preferred embodiment, which is to be read in connection with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.

Please refer to fig. 1 and fig. 2, which illustrate an embodiment of a display device according to the present invention. Fig. 1 shows the display device of the present invention viewed from the Y-Z plane, and fig. 2 shows the display device of the present invention viewed from the X-Z plane. The display device 100 of the present invention includes a backlight module 10, a switching uniaxial diffuser 20 and a display panel 30.

Referring to fig. 1, fig. 2 and fig. 4, fig. 4 is a schematic structural diagram of a backlight module of the display device shown in fig. 1. The backlight module 10 is adapted to generate light, and includes: a light emitting assembly 12, a light guide plate 14, and a light condensing film 16. The light guide plate 14 has a light incident surface and a light emitting surface. In this embodiment, the light is a planar light. The light emitting element 12 is adjacent to the light incident surface of the light guide plate 14 and is adapted to generate light. The light-condensing film 16 is disposed on the light guide plate 14. The light generated by the light emitting assembly 12 enters the light guide plate 14 through the light incident surface of the light guide plate 14, and is guided by the light guide plate 14 to exit through the light exiting surface and pass through the light collecting film 16, so as to generate light. The light output has a first beam pattern having light intensity of a predetermined value or more in a first viewing angle range θ 1 in a first direction (in the present embodiment, the X direction is the first direction, and in each of the later-described drawings, the first direction is parallel to the X axis direction). In the present embodiment, the light emitting element 12 may be, for example, a lamp or an array of light emitting diodes, and the light generated by the light emitting element 12 enters the light guide plate 14 through the light incident surface and is guided to the light emergent surface of the light guide plate 14 by the light guide plate 14 to exit. The bottom of the light guide plate 14 has a plurality of microstructures, and when light is transmitted to the microstructures in the light guide plate 14, the microstructures reflect the light and make the light incident on the light collecting film 16 at a predetermined angle. The light-gathering film 16 is provided with a plurality of inverse prisms 162 (as shown in fig. 4), and the light rays will be emitted towards the positive direction of the light-gathering film 16 after passing through the inverse prisms 162, thereby generating the light-gathering effect. In this embodiment, the predetermined value is 50% of the maximum value of the light-emitting brightness, so the first light pattern has a value of 50% or more of the maximum value of the light-emitting brightness of the backlight module 10 within the first viewing angle range θ 1, and in this embodiment, the first viewing angle range θ 1 is ± 20 degrees, that is, at the viewing angle ± 20 degrees, the brightness of the light ray is 50% of the maximum value of the light-emitting brightness of the backlight module 10. The backlight module 10 further includes a reflective sheet 18 disposed under the light guide plate 14.

The switchable uniaxial diffusion sheet 20 is disposed on the backlight module 10 and can be switched between a transparent state and a scattering state, wherein the scattering state has a diffusion angle in a first direction larger than that in other directions. The display panel 30 is disposed on the switching type uniaxial diffusion sheet 20. The light emitted from the backlight module 10 passes through the switching uniaxial diffusion sheet 20 and the display panel 30 in sequence to generate an image. FIG. 2 is a schematic diagram of a light path of the display device shown in FIG. 1 in a transparent state on a switching uniaxial diffuser viewed from an X-Z plane. When the switching type uniaxial diffusion sheet 20 is switched to the transparent state, the light output from the backlight module 10 passes through the switching type uniaxial diffusion sheet 20, keeps the first light type and has the light intensity of the predetermined value or more in the first visual angle range θ 1.

Referring to fig. 3A and 3B, fig. 3A is a schematic diagram of a light path of the display device shown in fig. 1 when the switchable uniaxial diffuser 20 is in a scattering state as viewed from a Y-Z plane. FIG. 3B is a schematic diagram of the light path of the display device shown in FIG. 1 when the switchable uniaxial diffuser 20 is in a scattering state as viewed from the X-Z plane. When switching formula unipolar diffusion piece 20 is switched into the scattering state, backlight unit 10's light-emitting is diffused and produces the second light type after through switching formula unipolar diffusion piece 20, the light ray of second light type has intensity more than the default in the second visual angle scope theta 2 on the first direction, and second visual angle scope theta 2 is greater than first visual angle scope theta 1, the second light type of diffusion after switching formula unipolar diffusion piece 20 switches to the scattering state is passed through to backlight unit 10's light-emitting promptly, its visual scope is greater than the visual scope of backlight unit 10's light-emitting and switches to the first light type after the transparent state through switching formula unipolar diffusion piece 20. In the present embodiment, the predetermined value is 50% of the maximum value of the light-emitting luminance, and therefore the second light pattern has a value of 50% or more of the maximum value of the light-emitting luminance of the backlight module 10 in the second viewing angle range.

As can be seen from a comparison between fig. 3A and fig. 3B, when the switching type uniaxial diffusion sheet 20 is in a scattering state, the original viewing angle range of the first light pattern is diffused by its angle in each direction, wherein the diffusion angle in the first direction is larger than the diffusion angles in the other directions. When applied to an actual display device, the viewing angle range in the first direction is larger than the viewing angle ranges in other directions, for example, the viewing angle range in the left-right direction of the display device is larger than the viewing angle ranges in the up-down direction, and the influence of the viewing angle range in the left-right direction on a user is important when the user is using the display device, and the influence of the viewing angle range in the up-down direction on the user is small. In the embodiment, since the light emitted from the backlight module 10 is diffused after passing through the switching uniaxial diffusion sheet 20 in a scattering state, the second viewing angle range θ 2 is larger than the first viewing angle range θ 1, that is, when the switching uniaxial diffusion sheet 20 is switched to the scattering state, the viewing range is increased, but the brightness is reduced because the light is distributed in a larger viewing angle range. Therefore, in the indoor or the outdoor light weak place, the image brightness in the specific view angle range can be reduced through the scattering state of the switching type single-axis diffusion sheet 20, so as to avoid the discomfort of the user caused by over-brightness, and the view angle range can be expanded by increasing the image brightness outside the specific view angle range. Compared with other diffusion sheets which can substantially uniformly diffuse the visual angle in each direction, the switching type single-shaft diffusion sheet enables the diffusion angle in the first direction to be larger than the diffusion angle in other directions, so that the light intensity in other directions can be still substantially concentrated in the direction of the front visual angle, and therefore the switching type single-shaft diffusion sheet can provide higher light intensity in the direction of the front visual angle compared with other diffusion sheets. Furthermore, there is a higher light intensity in the first direction due to the fact that most of the light is scattered into the first direction.

Referring to fig. 5, fig. 5 is a schematic structural view of a switching uniaxial diffuser in the display device shown in fig. 1. The switching uniaxial diffuser 20 includes: the liquid crystal display panel comprises a first transparent conductive layer 22, a second transparent conductive layer 24 and a polymer dispersed liquid crystal layer 26, wherein the polymer dispersed liquid crystal layer 26 is positioned between the first transparent conductive layer 22 and the second transparent conductive layer 24. The switching uniaxial diffusion sheet 20 further comprises a first transparent substrate 21 and a second transparent substrate 23, the first transparent substrate 21 is disposed on the first transparent conductive layer 22, the second transparent substrate 23 is disposed on the second transparent conductive layer 24, wherein the polymer dispersed liquid crystal layer 26 has a polymer base 262 and a plurality of liquid crystal particles 264, the liquid crystal particles 264 are disposed in the polymer base 262, each liquid crystal particle 264 is ellipsoidal and has a major axis, and the major axis corresponds to the first direction.

Referring to fig. 6A and 6B, fig. 6A is a schematic diagram of a light path when the display device 100 of the present invention is viewed from an X-Z plane and the switching uniaxial diffusion sheet is in a scattering state, and fig. 6B is a schematic diagram of a light path when the display device 100 of the present invention is viewed from a Y-Z plane and the switching uniaxial diffusion sheet is in a scattering state. When there is no voltage difference between the first transparent conductive layer 22 and the second transparent conductive layer 24, the liquid crystals in the liquid crystal particles 264 are randomly arranged, so that the polymer dispersed liquid crystal layer 26 is in a scattering state, and the light emitted from the backlight module 10 passes through the polymer dispersed liquid crystal layer 26 and is then diffused to generate the second light pattern. In the present embodiment, since the liquid crystal particles 264 are ellipsoidal, when light passes through the liquid crystal particles 264, the scattering angle in the long axis direction is larger than that in other directions, and since the long axis of the liquid crystal particles 264 is parallel to the first direction (parallel to the X axis in fig. 6A), the scattering angle of light in the first direction is larger than that in other directions.

Referring to fig. 7A and 7B, fig. 7A is a schematic diagram of a light path when the display device 100 of the present invention is viewed from an X-Z plane and the switching uniaxial diffusion sheet is in a transparent state, and fig. 7B is a schematic diagram of a light path when the display device 100 of the present invention is viewed from a Y-Z plane and the switching uniaxial diffusion sheet is in a transparent state. When the voltage difference is generated between the first transparent conductive layer 22 and the second transparent conductive layer 24, the liquid crystals in the liquid crystal particles 264 are regularly arranged, so that the polymer dispersed liquid crystal layer 26 is in a transparent state, and the light emitted from the backlight module 10 passes through the polymer dispersed liquid crystal layer 26 without diffusion, so that the first light type of the light is maintained.

The display device 100 of the present invention can concentrate the light emitted from the backlight module 10 in a narrow range under the environment of strong external light by disposing the switching type single-axis diffuser 20, so as to increase the brightness value in the range, and enable the user to see the image displayed by the display device 100. In an environment with weak external light, the light emitted from the backlight module 10 can be distributed more evenly in a larger viewing angle range in a specific direction, so that a user can view an image in the larger viewing angle range. Since most of the light is scattered only in a specific direction, it can have a higher luminance value in the specific direction. The switching type single-axis diffusion sheet enables the diffusion angle in the first direction to be larger than the diffusion angles in other directions, and enables the light intensity in other directions to be still approximately concentrated in the front viewing angle direction, so that compared with other diffusion sheets, the switching type single-axis diffusion sheet can provide higher light intensity in the front viewing angle direction.

The switching type single-axis diffusion sheet 20 of the present invention can switch the range of the viewing angle of the light according to the intensity of the external light, and can also make the display device have the function of peep prevention.

Please refer to fig. 8 and 9, which illustrate another embodiment of a display device according to the present invention. The display device 100 'of the present invention has substantially the same structure as the display device 100, and therefore the same elements are given the same reference numerals and description thereof is omitted, the display device 100' of the present embodiment includes a semi-transmissive viewing angle filter 40 in addition to the backlight module 10, the switching single-axis diffusion sheet 20 and the display panel 30, the semi-transmissive viewing angle filter 40 is disposed on the optical path of the backlight module 10, the switching single-axis diffusion sheet 20 and the display panel 30, and for example, the semi-transmissive viewing angle filter 40 may be disposed between the switching single-axis diffusion sheet 20 and the display panel 30 or the semi-transmissive viewing angle filter 40 is disposed on the display panel 30. The light transmittance of the transflective viewing angle filter 40 decreases along the normal direction of the transflective viewing angle filter 40 toward the first direction, and the light transmittance within a third viewing angle range θ 3 is greater than a predetermined value, wherein the predetermined value is between 40% and 60%. The third viewing angle range θ 3 is greater than the first viewing angle range θ 1 and less than the second viewing angle range θ 2 (please refer to fig. 2 at the same time). As shown in fig. 8, when the switching type single-axis diffuser 20 is switched to the transparent state, when the light passing through the switching type single-axis diffuser 20 passes through the half-transmissive viewing angle filter 40, the light intensity of the light exiting at different angles is attenuated due to the different light transmittance of the half-transmissive viewing angle filter 40 at different angles, wherein the light intensity of the light outside the third viewing angle range θ 3 is lower than a threshold value, and thus can be defined as invisible. As shown in fig. 9, when the switching type single-axis diffuser 20 is switched to the diffusion state, when the light passing through the switching type single-axis diffuser 20 passes through the half-transmissive viewing angle filter 40, the light intensity of the light emitted at different angles is attenuated due to the different light transmittance of the half-transmissive viewing angle filter 40 at each angle, wherein the light intensity of the light within the second viewing angle range θ 2 is higher than a threshold value, and thus can be defined as visible.

The definition of the privacy angle of a general display is that when the ambient illumination is 300-750 Lux (e.g., the illumination of a general office or conference room), and the brightness (nits) at the privacy angle/the brightness (nits) at the positive viewing angle is less than or equal to 1.5%, the viewer cannot clearly see the image content of the display at the privacy angle, which is defined as invisible. If the brightness (nits) at the peep-proof angle/the brightness (nits) at the positive viewing angle is greater than 1.5%, the image content of the display can be clearly seen, which is defined as visible. However, under other, more strict definitions of invisibility, the definition of the privacy angle is an angle where the luminance (nits)/the luminance of the positive viewing angle (nits) is less than or equal to 1% or 0.8%. Therefore, the definition of the peep-proof angle can be set according to the requirement, wherein 45 degrees are mostly set as the peep-proof angle, and 30 degrees are set as the peep-proof angle for a small part. Wherein the positive viewing angle is defined as 0 degrees or an angle close to 0 degrees at which the brightness is highest. The measurement can be measured by a Conscope measurement instrument or by a rotary arm with the instrument BM7, PR650, etc.

As shown in fig. 10, it shows that the transmittance of light of the transflective viewing angle filter 40 of the present embodiment can be reduced to less than 50% outside the range of ± 45 degrees, in the present embodiment, the third viewing angle range θ 3 is ± 45 degrees, and the transmittance of light is 50%. The light output of the backlight module 10 is a first light type, as described above, the first light type has a brightness value more than 50% of the maximum value of the light output brightness within the first viewing angle range θ 1(± 20 degree angle), that is, the brightness value outside the first viewing angle range θ 1(± 20 degree angle) is less than 50% of the maximum value of the light output brightness, therefore, when the switching type single-axis diffusion sheet 20 is switched to the transparent state, the light output of the backlight module 10 keeps the first light type after passing through the switching type single-axis diffusion sheet 20, after the light of the first light type passes through the semi-transmissive viewing angle filter 40, because the penetration rate of the light outside the third viewing angle range θ 3(± 45 degree angle) is reduced to less than 50%, and the third viewing angle range θ 3 is greater than the first viewing angle range θ 1. Therefore, after the first light beams pass through the transflective viewing angle filter 40, the brightness of the light outside the third viewing angle range θ 3 can be reduced to be invisible, thereby achieving the effect of peep prevention. When the switching type single-axis diffusion sheet 20 is switched to the diffusion state, the brightness value of the light passing through the switching type single-axis diffusion sheet 20 is more average in the second viewing angle range θ 2 due to the diffusion effect, the second viewing angle range θ 2 is larger than the third viewing angle range θ 3, and after the diffused light passes through the half-transmissive viewing angle filter 40, even if the transmittance of the light outside the third viewing angle range θ 3 is reduced to below 50%, the light passing through the half-transmissive viewing angle filter 40 still has sufficient brightness to make the image visible, so that the display device 100' can be switched between the peep-proof mode and the non-peep-proof mode by switching the switching type single-axis diffusion sheet 20 between the transparent state and the diffusion state. The structure of the transflective viewing angle filter 40 will be described below.

Please refer to fig. 11 and 12, which illustrate an embodiment of a transflective viewing angle filter of a display device according to the present invention. Fig. 11 shows that the half-transmissive viewing angle filter 40 is provided between the switching single-axis diffusion sheet 20 and the display panel 30, and fig. 12 shows that the half-transmissive viewing angle filter 40 is provided on the display panel 30, that is, the display panel 30 is provided between the half-transmissive viewing angle filter 40 and the switching single-axis diffusion sheet 20. The half-transmissive viewing angle filter 40 of the present invention includes: the liquid crystal display panel comprises a first polarizer 42, a second polarizer 46 and a first phase compensation film 44, wherein the first phase compensation film 44 is located between the first polarizer 42 and the second polarizer 46, the first polarizer 42 has a first penetrating axis L42, the second polarizer 46 has a second penetrating axis L46, the first penetrating axis L42 is parallel to the second penetrating axis L46, and the first phase compensation film 44 has a first liquid crystal polymer layer. The liquid crystal polymer of the first liquid crystal polymer layer has a first optical axis, and the first optical axis is obliquely arranged relative to the first polarizer 42 and the second polarizer 46, but a first projection of the first optical axis on the first polarizer 42 and the second polarizer 46 is parallel to or perpendicular to the first transmission axis L42 and the second transmission axis L46, and the first projection is perpendicular to the first direction, so that the light passing through the first polarizer 42 and the first phase compensation film 44 generates a phase retardation in the first direction, and the larger the incident angle is, the larger the phase retardation is, the more the light is absorbed by the second polarizer 46, and the transmittance of the light outside the range of ± 45 degrees in the first direction is reduced to below 50%. The display panel 30 is disposed with a polarizer 34 and a polarizer 32 on the top and bottom, the polarizer 32 has a penetration axis L32, the polarizer 34 has a penetration axis L34, and the penetration axis L32 is perpendicular to the penetration axis L34. In the configuration shown in FIG. 11, the axis of penetration L32 of polarizer 32 is parallel to the axis of penetration L46 of second polarizer 46. In the structure shown in fig. 12, the transmission axis L34 of the polarizer 34 is parallel to the transmission axis L42 of the first polarizer 42, i.e. the transmission axes of the polarizers adjacent to the transflective viewing filter 40 and the display panel 30 must be parallel, and if the directions of the transmission axes of the two overlapped polarizers are the same, the effect is equal to that of one polarizer having the transmission axis in the same direction, so that the second polarizer 46 may be omitted in the structure shown in fig. 11, and the first polarizer 42 may be omitted in the structure shown in fig. 12.

Please refer to fig. 13 and 14, which illustrate another embodiment of the transflective viewing angle filter of the display device according to the present invention. Fig. 13 shows that the half-transmissive viewing angle filter 40 ' is provided between the switching single-axis diffusion sheet 20 and the display panel 30, and fig. 14 shows that the half-transmissive viewing angle filter 40 ' is provided on the display panel 30, that is, the display panel 30 is provided between the half-transmissive viewing angle filter 40 ' and the switching single-axis diffusion sheet 20. The structure of the half-transmissive viewing angle filter 40 ' of the present embodiment is substantially the same as the structure of the half-transmissive viewing angle filter 40 shown in fig. 11 and 12, and therefore, the same reference numerals are given to the same elements and descriptions thereof are omitted, the difference between the structure of the half-transmissive viewing angle filter 40 ' of the present embodiment and the structure of the half-transmissive viewing angle filter 40 shown in fig. 12 and 13 is that the half-transmissive viewing angle filter 40 ' of the present embodiment includes a second phase compensation film 43, a third polarizer 41 and a polarizer 45 in addition to a first polarizer 42, a second polarizer 46 and a first phase compensation film 44, the second phase compensation film 43 is located between the first polarizer 42 and the third polarizer 41, the third polarizer 41 has a third transmission axis L41, the second phase compensation film 43 has a second liquid crystal polymer layer, liquid crystal molecules of the second liquid crystal polymer layer have a second optical axis, and the second optical axis is perpendicular to the surface of the second phase compensation mode 43, and the third penetrating axis L41 is parallel to the first penetrating axis L42 and the second penetrating axis L46. In the present embodiment, the second phase compensation film 43 is disposed between the third polarizer 41 and the polarizer 45, the third transmission axis L41 of the third polarizer 41 is parallel to the transmission axis L45 of the polarizer 45, and the third penetrating axis L41 is parallel to the first penetrating axis L42 and the second penetrating axis L46, the second phase compensation film 43 makes the light penetration rate below 50% outside the range of + -45 degree angle in the directions of 45 degree, 135 degree, 225 degree and 315 degree with the first direction, thus, after the light passes through the first phase compensation film 44 and the second phase compensation film 43, phase retardation is generated in the first direction and the directions forming 45 degrees, 135 degrees, 225 degrees and 315 degrees with the first direction respectively, so that the transmittance of light outside the range of + -45 degrees in the first direction and the directions at 45 degrees, 135 degrees, 225 degrees and 315 degrees from the first direction is reduced to below 50%. In addition, in the configurations shown in fig. 13 and 14, since the first penetration axis L42 of the first polarizer 42 is parallel to the penetration axis L45 of the polarizer 45, the first polarizer 42 or the polarizer 45 may be omitted.

In another embodiment, the transflective viewing filter further includes a third phase compensation film and a fourth polarizer, i.e. the second phase compensation film 43 and the third polarizer 41 in fig. 13 and 14 are replaced by the third phase compensation film and the fourth polarizer, and the structures are the same, so the illustration thereof is omitted here. The third phase compensation film is located between the first polarizer and the fourth polarizer, the fourth polarizer has a fourth penetration axis, the third phase compensation film has a third liquid crystal polymer layer, liquid crystal molecules of the third liquid crystal polymer layer have a third optical axis, and projections of the third optical axis on the second polarizer and the fourth polarizer are parallel or perpendicular to the second penetration axis and the fourth penetration axis, the fourth penetration axis is parallel to the first penetration axis and the second penetration axis, and the phase delay characteristics of the first phase compensation film 44 and the third phase compensation film are different. The present embodiment is different from the embodiments of fig. 13 and 14 in that the structure of the third phase compensation film is similar to that of the first phase compensation film 44, the optical axes of the liquid crystal molecules are all inclined, but the liquid crystal polymer of the liquid crystal polymer layer has different characteristics, the phase retardation is determined by the product of the refractive index difference and the thickness of the liquid crystal polymer, and the phase retardation is different due to the difference of the product of the refractive index difference and the thickness. In addition, in the embodiment, since the optical axes of the liquid crystal molecules are all inclined, and the optical axis direction of the liquid crystal molecules also affects the phase retardation, the first phase compensation film 44 and the third phase compensation film can achieve different phase retardations by disposing liquid crystal polymers with different characteristics, so that the transmittance of light outside the range of ± 45 degrees in the first direction is reduced to 50% or less.

Please refer to fig. 15 and 16, which illustrate another embodiment of the transflective viewing angle filter of the display device according to the present invention. Fig. 15 shows that the transflective viewing angle filter 50 is disposed between the switching single-axis diffusion sheet 20 and the display panel 30, and fig. 16 shows that the transflective viewing angle filter 50 is disposed on the display panel 30, that is, the display panel 30 is disposed between the transflective viewing angle filter 50 and the switching single-axis diffusion sheet 30A uniaxial diffuser 20. The transflective viewing angle filter 50 of the present embodiment includes a fifth polarizer 52, a sixth polarizer 56, a half-wave plate 51 and a fourth phase compensation film 55. The fifth polarizer 52 has a fifth penetration axis L52, the sixth polarizer 56 has a sixth penetration axis L56, the half-wave plate 51 and the fourth phase compensation film 55 are located between the fifth polarizer 52 and the sixth polarizer 56, the fourth phase compensation film 55 has a fourth liquid crystal polymer layer, the liquid crystal polymer of the fourth liquid crystal polymer layer has a fourth optical axis, the fourth optical axis is perpendicular to the surface of the fourth phase compensation film 55, and an included angle between the slow axis L51 of the half-wave plate 51 and the fifth penetration axis L52 is 22.5^o15o or 62.5o 15o, and the angle between the sixth penetration axis L56 and the fifth penetration axis L52 is 45o 15o or 125o 15 o. The fourth phase compensation film 55 makes the transmittance of light outside the range of ± 45 degrees in the directions of 45 degrees, 135 degrees, 225 degrees and 315 degrees from the first direction be less than 50%, so that the half-wave plate 51 is matched to generate phase retardation to make the transmittance of light return to the first direction in the direction of less than 50%. Polarizer 54 may be disposed between fourth phase compensation film 55 and half-wave plate 51, and a transmission axis L54 of polarizer 54 may be parallel to a sixth transmission axis L56 of sixth polarizer 56, and in the configuration of fig. 15, sixth transmission axis L56 of sixth polarizer 56 is parallel to transmission axis L32 of polarizer 32, so that one of sixth polarizer 56 or polarizer 32 may be omitted. In the configuration of FIG. 16, the fifth polarizer 52 (not shown) may be omitted because the fifth transmission axis L52 (not shown) of the fifth polarizer 52 (not shown) is parallel to the transmission axis L34 of the polarizer 34 of the display panel 30.

Please refer to fig. 17 and 18, which illustrate another embodiment of the transflective viewing angle filter of the display device according to the present invention. Fig. 17 shows that the half-transmissive viewing angle filter 60 is provided between the switching single-axis diffusion sheet 20 and the display panel 30, and fig. 18 shows that the half-transmissive viewing angle filter 60 is provided on the display panel 30, that is, the display panel 30 is provided between the half-transmissive viewing angle filter 60 and the switching single-axis diffusion sheet 20. The structure of the transflective viewing angle filter 60 of the present embodiment is substantially the same as the structure of the transflective viewing angle filter 40 shown in fig. 15 and 16, and therefore, the same reference numerals are given to the same elements and descriptions thereof are omitted, in the present embodiment, the transflective viewing angle filter 60 further includes a fifth phase compensation film 62 in addition to the polarizer 54, the sixth polarizer 56, the half-wave plate 51 and the fourth phase compensation film 55, the half-wave plate 51 is disposed between the fourth phase compensation film 55 and the fifth phase compensation film 62, the fifth phase compensation film 62 has a fifth liquid crystal polymer layer, the liquid crystal polymer of the fifth liquid crystal polymer layer has a fifth optical axis, and the fifth optical axis is perpendicular to the surface of the fifth phase compensation film 62. The transflective viewing filter 60 further includes a polarizer 64 and a polarizer 66, wherein the transmission axis L64 of the polarizer 64 is parallel to the transmission axis L66 of the polarizer 66, and in the configuration shown in fig. 18, the polarizer 64 can be omitted because the transmission axis L64 of the polarizer 64 is parallel to the transmission axis L34 of the polarizer 34 of the display panel 30.

In another embodiment, the transflective viewing angle filter includes: a seventh polarizer, an eighth polarizer, a ninth polarizer, a sixth phase compensation film and a seventh phase compensation film, the arrangement and structure of which are the same as those in fig. 13 and 14, and therefore the drawings are omitted, wherein the seventh polarizer has a seventh transmission axis, the eighth polarizer has an eighth transmission axis, the ninth polarizer has a ninth transmission axis, the sixth phase compensation film is located between the seventh polarizer and the eighth polarizer, the seventh phase compensation film is located between the eighth polarizer and the ninth polarizer, the sixth phase compensation film has a sixth liquid crystal polymer layer, the liquid crystal molecules of the sixth liquid crystal polymer layer have a sixth optical axis, the sixth optical axis is perpendicular to the surface of the sixth phase compensation film, the seventh phase compensation film has a seventh liquid crystal polymer layer, the liquid crystal molecules of the seventh liquid crystal polymer layer have a seventh optical axis, and the seventh optical axis is perpendicular to the surface of the seventh phase compensation film, the seventh penetrating shaft, the eighth penetrating shaft and the ninth penetrating shaft are parallel and form an included angle of 45 +/-15 DEG with the first direction^oOr 125^o±15^oThe sixth phase compensation film and the seventh phase compensation film have different phase retardation characteristics. The difference from the embodiments of FIGS. 13 and 14 is that the optical axes of the liquid crystal molecules of the sixth phase compensation film and the seventh phase compensation film are both disposed vertically, and the retardation is a function of the refractive index of the liquid crystal polymerThe sixth phase compensation film and the seventh phase compensation film can achieve different phase retardation amounts by arranging liquid crystal polymers with different characteristics, so that the transmittance of light outside the range of +/-45 degrees in the first direction is reduced to below 50%.

Referring to fig. 19, fig. 19 is a schematic structural diagram of a transflective viewing angle filter having a plurality of transflective partitions. In one embodiment, the transflective viewing filter 70 includes a plurality of partition walls 71, the partition walls 71 are arranged along the first direction, and two adjacent partition walls 71 of the partition walls 71 are spaced apart by a predetermined distance d to form a light channel. The barrier ribs 71 may include a gray photoresist or use a dye or pigment to make the light transmittance of the barrier ribs 71 between 10% and 60%, preferably between 40% and 50%, preferably 50%. Thus, the transmittance of the light outside the range of ± 45 degrees in the first direction is reduced to below 50%.

The display device 100 'of the present invention can be switched between the privacy mode and the non-privacy mode by providing the half-transmissive viewing angle filters 40, 40', 50, 60, and 70 and switching the switching type uniaxial diffusion sheet 20 between the transparent state and the diffusion state.

The display device 100 of the present invention utilizes the characteristic that the light-condensing backlight module 10 and the switching type single-axis diffuser 20 can be switched between a transparent state and a diffusion state, when external light is strong, the switching type single-axis diffuser 20 is switched to the transparent state, so that light is concentrated in a certain viewing angle range to obtain higher brightness, a user can watch a clear image, in an environment with weak external light, the display device 100 does not need high brightness, the switching type single-axis diffuser 20 is switched to the diffusion state, the viewing angle range of the light is increased, the brightness is reduced, and the clear image can still be watched. Thus, the display device 100 of the present invention does not need to add extra light sources and current for driving the light sources, and the brightness of the display device 100 can be adjusted according to the intensity of the light of the external environment by using the switching type single-axis diffuser 20.

In addition, the display device 100 of the present invention further includes a semi-transparent viewing angle filter 40, which attenuates the brightness below a predetermined value outside a predetermined viewing angle range, and matches with the characteristic that the switching type single-axis diffusion sheet 20 switches between the transparent state and the scattering state, so that the display device 100' has a peep-proof function and can switch between a peep-proof mode and a non-peep-proof mode.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the scope of the invention, which is intended to cover all the modifications and equivalents of the claims and the specification, which are included in the invention. Moreover, it is not necessary for any embodiment or claim of the invention to address all of the objects, advantages, or features disclosed herein. In addition, the abstract and the title of the invention are provided for assisting the retrieval of patent documents and are not intended to limit the scope of the invention. Furthermore, the terms "first", "second", and the like in the description or the claims are used only for naming elements (elements) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit on the number of elements.

Description of the reference numerals

10: backlight module

12: light emitting assembly

14: light guide plate

16: light-gathering film

18: reflector plate

20: switching type single-shaft diffusion sheet

21: a first transparent substrate

22: a first transparent conductive layer

23: a second transparent substrate

24: second transparent conductive layer

26: polymer dispersed liquid crystal layer

30: display panel

32: polaroid

34: polaroid

40. 40': semi-transparent viewing angle filter

41: third polarizer

42: a first polarizer

43: second phase compensation film

44: first phase compensation film

45: polaroid

46: second polarizer

50: semi-transparent viewing angle filter

51: half-wave plate

52: fifth polarizer

54: polaroid

55: fourth phase compensation film

56: sixth polarizer

60: semi-transparent viewing angle filter

62: fifth phase compensation film

64: polaroid

66: polaroid

70: semi-transparent viewing angle filter

71: partition wall

100. 100': display device

162: inverse prism

262: polymer substrate

264: liquid crystal microparticles

L32: penetrating shaft

L34: penetrating shaft

L41: third penetrating shaft

L42: a first penetrating shaft

L45: penetrating shaft

L46: second penetrating shaft

L51: slow axis

L52: fifth penetration axis

L54: penetrating shaft

L56: sixth penetration shaft

L64: penetrating shaft

L66: penetrating shaft

θ 1: first range of viewing angles

θ 2: second range of viewing angles

θ 3: third range of viewing angles

d: distance between each other

X: x axis

Y: y-axis

Z: z axis

Claims

1. A display device comprises a backlight module, a switching single-axis diffuser, a display panel and a semi-transparent viewing angle filter,

the backlight module is suitable for generating light emission, and the light emission has a first light type which has light intensity more than a preset value in a first visual angle range in a first direction;

the switching type single-shaft diffusion sheet is arranged on the backlight module and is switched between a transparent state and a scattering state, and the diffusion angle of the scattering state in the first direction is larger than that in other directions;

the display panel is arranged on the switching type uniaxial diffusion sheet,

the light emitting device comprises a switching type single-axis diffusion sheet, a display panel, a switching type single-axis diffusion sheet, a first light type, a second light type and a backlight module, wherein the light emitting light generated by the backlight module sequentially passes through the switching type single-axis diffusion sheet and the display panel to generate an image;

the semi-transparent visual angle filter is arranged on the light path of the backlight module, the switching type single-axis diffusion sheet and the display panel, the light transmittance of the semi-transparent visual angle filter decreases progressively towards the first direction along the normal direction of the semi-transparent visual angle filter, the light transmittance in a third visual angle range is larger than a preset value, the third visual angle range is larger than the first visual angle range and smaller than the second visual angle range,

wherein the semi-transmissive viewing angle filter comprises: a first polarizer, a second polarizer and a first phase compensation film, wherein the first phase compensation film is sandwiched between the first polarizer and the second polarizer, the first polarizer has a first penetrating axis, the second polarizer has a second penetrating axis, the first penetrating axis is parallel to the second penetrating axis, the first phase compensation film has a first liquid crystal polymer layer, wherein the liquid crystal polymer of the first liquid crystal polymer layer has a first optical axis, the axial direction of a first projection of the first optical axis on the first polarizer and the second polarizer is parallel or perpendicular to the first penetrating axis and the second penetrating axis, and the axial direction of the first projection is perpendicular to the first direction,

the semi-transparent viewing angle filter further comprises a second phase compensation film and a third polarizer, the second phase compensation film is located between the first polarizer and the third polarizer, the third polarizer is provided with a third penetrating axis, the second phase compensation film is provided with a second liquid crystal polymer layer, liquid crystal molecules of the second liquid crystal polymer layer are provided with a second optical axis, the second optical axis is perpendicular to the surface of the second phase compensation film, and the third penetrating axis is parallel to the first penetrating axis and the second penetrating axis.

2. The display device according to claim 1, wherein the switching uniaxial diffuser sheet comprises a first transparent conductive layer, a second transparent conductive layer, and a polymer dispersed liquid crystal layer,

the polymer dispersed liquid crystal layer is positioned between the first transparent conducting layer and the second transparent conducting layer,

the polymer dispersed liquid crystal layer comprises a polymer substrate and a plurality of liquid crystal particles, wherein the liquid crystal particles are arranged in the polymer substrate, each liquid crystal particle is ellipsoidal and has a long axis, and the long axis is substantially parallel to the first direction,

when the first transparent conducting layer and the second transparent conducting layer have no voltage difference, the liquid crystals in the liquid crystal particles are arranged in a scattered manner, so that the polymer dispersed liquid crystal layer is in the scattering state.

3. The display device of claim 1, wherein the predetermined value is between 40% and 60%.

4. The display device according to claim 1, wherein the transflective viewing angle filter comprises a fifth polarizer, a sixth polarizer, a half-wave plate and a fourth phase compensation film, the fifth polarizer has a fifth transmission axis, the sixth polarizer has a sixth transmission axis, the half-wave plate and the fourth phase compensation film are positioned between the fifth polarizer and the sixth polarizer, the fourth phase compensation film has a fourth liquid crystal polymer layer, the liquid crystal polymer of the fourth liquid crystal polymer layer has a fourth optical axis, the fourth optical axis is perpendicular to the surface of the fourth phase compensation film, the included angle between a slow axis of the half-wave plate and the fifth penetrating axis is 22.5 degrees +/-15 degrees or 62.5 degrees +/-15 degrees, and the included angle between the sixth penetrating shaft and the fifth penetrating shaft is 45 degrees +/-15 degrees or 125 degrees +/-15 degrees.

5. The display device as claimed in claim 1, wherein the transflective viewing angle filter is disposed between the switching uniaxial diffuser and the display panel.

6. The display device as claimed in claim 1, wherein the display panel is disposed between the transflective viewing angle filter and the switching uniaxial diffuser.

7. The display device of claim 1, wherein the transflective viewing filter comprises a plurality of partition walls, the partition walls are arranged along the first direction, and two adjacent partition walls of the partition walls are separated by a predetermined distance to form a light channel.

8. The display device of claim 7, wherein the plurality of barrier ribs comprise a gray photoresist, a dye or a pigment, and a light transmittance of the plurality of barrier ribs is between 10% and 60%.

9. The display device of claim 1, wherein the first range of viewing angles is ± 20 degrees.

10. The display device of claim 1, wherein the third range of viewing angles is ± 45 degrees.

11. A display device comprises a backlight module, a switching single-axis diffuser, a display panel and a semi-transparent viewing angle filter,

the display panel is arranged on the switching type uniaxial diffusion sheet,

the semi-transparent visual angle filter further comprises a third phase compensation film and a fourth polaroid, wherein the third phase compensation film is located between the second polaroid and the fourth polaroid, the fourth polaroid is provided with a fourth penetrating shaft, the third phase compensation film is provided with a third liquid crystal polymer layer, a liquid crystal polymer of the third liquid crystal polymer layer is provided with a third optical axis, the third optical axis is parallel or vertical to the axial direction of a third projection on the second polaroid and the fourth polaroid, the second penetrating shaft and the fourth penetrating shaft are parallel to the first penetrating shaft and the second penetrating shaft, and the phase delay characteristics of the first phase compensation film and the third phase compensation film are different.

12. A display device comprises a backlight module, a switching single-axis diffuser, a display panel and a semi-transparent viewing angle filter,

the display panel is arranged on the switching type uniaxial diffusion sheet,

the semi-transparent viewing angle filter further comprises a fifth polarizer, a sixth polarizer, a half-wave plate and a fourth phase compensation film, the fifth polarizer has a fifth transmission axis, the sixth polarizer has a sixth transmission axis, the half-wave plate and the fourth phase compensation film are located between the fifth polarizer and the sixth polarizer, the fourth phase compensation film has a fourth liquid crystal polymer layer, the liquid crystal polymer of the fourth liquid crystal polymer layer has a fourth optical axis, the fourth optical axis is perpendicular to the surface of the fourth phase compensation film, an included angle between a slow axis of the half-wave plate and the fifth transmission axis is 22.5 ° ± 15 ° or 62.5 ° ± 15 °, and an included angle between the sixth transmission axis and the fifth transmission axis is 45 ° ± 15 ° or 125 ° ± 15 °,

the semi-transparent viewing angle filter further comprises a fifth phase compensation film, the half-wave plate is arranged between the fourth phase compensation film and the fifth phase compensation film, the fifth phase compensation film is provided with a fifth liquid crystal polymer layer, the liquid crystal polymer of the fifth liquid crystal polymer layer is provided with a fifth optical axis, and the fifth optical axis is perpendicular to the surface of the fifth phase compensation film.

13. A display device comprises a backlight module, a switching single-axis diffuser, a display panel and a semi-transparent viewing angle filter,

the display panel is arranged on the switching type uniaxial diffusion sheet,

the semi-transparent viewing angle filter further comprises: a seventh polarizer, an eighth polarizer, a ninth polarizer, a sixth phase compensation film and a seventh phase compensation film, wherein the seventh polarizer has a seventh transmission axis, the eighth polarizer has an eighth transmission axis, the ninth polarizer has a ninth transmission axis, the sixth phase compensation film is located between the seventh polarizer and the eighth polarizer, the seventh phase compensation film is located between the eighth polarizer and the ninth polarizer, the sixth phase compensation film has a sixth liquid crystal polymer layer, the liquid crystal molecules of the sixth liquid crystal polymer layer have a sixth optical axis, the sixth optical axis is perpendicular to the surface of the sixth phase compensation film, the seventh phase compensation film has a seventh liquid crystal polymer layer, the liquid crystal molecules of the seventh liquid crystal polymer layer have a seventh optical axis, and the seventh optical axis is perpendicular to the surface of the seventh phase compensation film, the seventh, eighth, and ninth penetration axes are parallel, and the sixth and seventh phase compensation films have different phase retardation characteristics.